<!DOCTYPE html>
<html>
<head>
  <style type="text/css" media="screen">
    .red {
        background-color: red;
    }

    .green {
        background-color: green;
    }
    div {
      height: 100px;
      width: 100px;
    }

    .backfaceVisible {
      transform: rotateY(180deg);
      backface-visibility: visible;
    }

    .backfaceHidden {
      transform: rotateY(180deg);
      backface-visibility: hidden;
    }
  </style>
</head>
<body>
  <!-- In the pixel results, two green squares should be visible. -->
  <div class="red">
    <div class="backfaceVisible green">
    </div>
  </div>
  <p>
  <div class="green">
    <div class="backfaceHidden red">
    </div>
  </div>
</body>
</html>
